In the field of turning and boring machines, it is frequently necessary to use a multiple tool turret for carrying an array of boring bars for particular machining operations. Many prior art assemblies utilize a rotatable indexable spindle in a turret housing, wherein a large facial area of the spindle is provided to provide a large swing radius for clearing previously used tools out of the way for a new tool entry as a turret is indexed. The turret assemblies frequently carry boring bars which extend from the face of the tool turret spindle in a cantilever fashion, and are subject to high deflection in and of themselves, but, when coupled with the diaphragming or overturning of the radial plate which supports them, the deflection may be compounded.
When vibrations are encountered, the boring bars can vibrate an objectionable amount. It has been the previous practice, to provide a relatively stiff turret bearing mounting assembly, to attempt to prevent the turret spindle face from deflecting an objectionable amount, and other prior art efforts have been directed at providing stiff boring bars, which are not discussed in this disclosure. Applicant has determined that very little damping exists in the prior art assemblies to counteract any vibrational movements which may occur on a cantilevered boring bar.
Applicant has obviated the difficulties inherent in the prior art devices, by a novel damped tool turret, having a relatively low static stiffness, but a relatively high dynamic stiffness, due to the inherent damping properties of the assembly.